This invention relates to systems and methods for providing and managing Internet protocol (IP) connection oriented services.
The Internet Protocol was initially defined for connectionless services. In a typical IP network, traffic is carried in packets which are individually routed at the system nodes. The services currently provided in such networks normally operate on a best effort basis, i.e. the network will always attempt to route a packet to its destination, but cannot guarantee delivery e.g. under overload conditions There is now a keen interest in the provision of voice services over the Internet where costs are significantly less than those associated with the conventional PSTN. However, the adaptation of what is effectively a high priority connection oriented service to a xe2x80x98best effortxe2x80x99 connectionless or packet system has introduced a number of significant problems. In particular, if an Internet voice service is to obtain universal acceptance, it must provide a quality of service similar to that currently provided by conventional voice networks.
A number of workers are currently addressing this problem. For example, the current Internet Ipv4 protocol includes a TOS octet and Ipv6 a traffic class octet which allows a number of priority levels to be defined to support some degree of traffic engineering in an IP network.
The IETF Differentiated Services Working Group has recently defined a method whereby traffic is classified at a priority level and is policed on entry to an IP network. Traffic behaviour on internal links (per hop behaviour) is specified. It is expected that using these methods then service level agreements can be offered to users provided that the number of internal hops is low and also provided that the percentage of high priority traffic is a small percentage of the total traffic.
Other IETF Working Groups have defined protocols providing some degree of connection orientation. These are:
Multi Protocol Label Switching (MPLS) includes the ability to tunnel through many routing stages and to do so using explicit routing rather than hop-by-hop routing. This is a form of connection orientation.
Layer 2 Tunnelling Protocol (LTP) provides a signalling system to dynamically create and delete IP point to point protocol (PPP) sessions end to end across a tunnel. These sessions are allocated bandwidth, are timed for billing purposes, and are explicitly deleted on completion. This is a fully connection oriented paradigm.
Connection orientation is of particular value in the provision of carrier network services to individual users or to user networks. In particular it simplifies the tasks of:
Guaranteeing bandwidth.
Ensuring Quality of service.
Authenticating end user identities.
Preventing fraudulent access or misuse of resources.
Existing Layer 2 networks such as Frame Relay or ATM are able to provide an effective control framework to provide bandwidth accounting. However their control protocols are not sufficiently integrated into the Layer 3 IP network functionality to ensure that QoS characteristics of user services are maintained. This has limited the exploitation of this characteristic and has thus failed to resolve the provision of QoS in the Internet.
An object of the invention is to minimise or to overcome the above disadvantage.
A further object of the invention is to provide an improved arrangement and method for providing connection oriented services in a connectionless network.
According to the invention there is provided a method of carrying connection oriented services over a connectionless network, the method comprising establishing engineering tunnels in the connectionless network establishing user tunnels within the engineering tunnels, and transporting said connection oriented services via said user tunnels.
According to a further aspect of the invention there is provided A connectionless network arrangement for switching connection oriented services, the arrangement comprising means for establishing engineering tunnels in the connectionless network, means for establishing user tunnels within the engineering tunnels, and means for transporting said connection oriented services via said user tunnels.
Advantageously, management of the connection oriented services is performed by the transmission of signalling information via the engineering tunnels.
In a further aspect the invention provides a network node router for switching connection oriented services and non-connection oriented services over a connectionless packet network comprising a plurality of nodes and provided with tunnels within which tunnels the connection oriented services are carried, the router comprising an inner switch core arranged to handle packet traffic that is routed from node to node and not contained within a said tunnel and incorporating a set of ingress functions coupled to respective ingress ports, and a set of egress functions coupled to respective egress ports, and wherein the router further incorporates means for identifying traffic contained within a said tunnel so as to permit that traffic to pass directly through the node.
In yet another aspect, the invention provides a method of packet switching at a network node connection oriented services and non-connection oriented services over a connectionless packet network provided with tunnels within which the connection oriented services are carried, the method comprising determining at said network node whether a packet received at said node is or is not contained within a said tunnel, determining for each said packet not contained within a tunnel an adjacent node to which to route that packet, and permitting packets determined to be contained within a said tunnel to pass through the node within that tunnel.
The invention further comprises a connection control architecture to provide a range of connection oriented services in Internet Protocol networks. The architecture, which applies recursively at multiple levels, can be used to establish engineering tunnels in the physical network and user tunnels within these engineering tunnels.
The invention further relates to an architecture for the systematic provision of connection oriented services with managed bandwidth, guaranteed Quality of Service and user authentication. In the prior art such capabilities are provided by a separate network such as Frame Relay or ATM, such networks operate at Layer 2 leaving the Internet work to operate at Layer 3. In this invention a single network operates at Layer 2 or Layer 3 interchangeably according to the function required.
In a preferred embodiment, the network comprises a hierarchy of sub-networks. Within each sub-network, each node has a first database of topology information relating to that sub-network, and a second database of summary information relating to other sub-networks. One node in each sub-network is defined as a peer group leader for that sub-network, and distributes the summary information to the other nodes of that sub-network